Reflector.



UNIT D STATES Patented May 23, 1905.

PATENT OF CE.

WVALTER DA. RYAN, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

REFLECTOR.

SPECIFICATION forming part of Letters Patent No. 790,399, dated May 23, 1905.

Application filed November 2,1903. Serial No. 179,502.

To (all whm'n, it concern:

Be it known that I, WALTER DA. RYAN, a subject of the King of Great Britain, residing at Lynn, county of Essex, State of Massachu:

setts, have invented certain new and useful Improvements in Reflectors, of which the following is a specification.

The object of my present invention is the provision of improved means by which a proper distribution of the light emanating from a source can be obtained.

More particularly, my invention relates to means which are intended to be used in conjunction with such a source of light as an arclamp.

My invention consists in certain features of construction and arrangement, all of which will be pointed out with particularity in the claims annexed to and forming part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawings, in whichI have illustrated embodiments of my invention.

In the drawings, Figure 1 is a perspective view illustrating an arc-lamp provided with one form of my improved light-distributing means. Fig. 2 isa partial sectional elevation showing the same construction as Fig. 1. Fig. 3 is a view showing a modified form of the reflector shown in Fig. 1.

Referring to Figs; 1 and 2, 1 is a conventional representation of an arc-lamp, in which 2 and 3 are the electrodes between which the light-producing arc extends. The reflector 4: is carried by the lamp so that its reflectingsurface is located above the are. In the construction shown in the drawings the reflector is of the general shape of an inverted cone. An orifice 5 is formed centrally in the reflector, through which the upper electrode and the supporting mechanism for the lower electrode pass. The central portion of the reflector is shaped to form an upturned cylindrical flange 6. Suitable screws 7, which engage this flange, maybe employed to secure the reflector to the lamp structure.

In the form shown in Figs. 1 and 2 of the drawings a series of concentric ridges or corrugations 8 are formed on the under surface of the reflector from the center of the reflector outward.

The amplitude of the corrugations or ridges measured in the direction perpendicular to the general surface of the reflector,or, in other words, their height, increases from the central flange 6 outward. With this construction the light emanating from the source which is received by the inner sides of the ridges and reflected downward is more satisfactorily distributed than would be the case if all the ridges were of the same height. The construction described gives a highlyadvantageous distribution of light below the reflector; but I make no claim to this arrangement of ridges in this application, as I have already claimed it in another application.

I prefer to make the reflector 4: out of sheet metal or other material which is opaque. In order to prevent a shadow being cast by the reflector above the source of light, which may be objectionable in some cases, as where the arc-lamp or other sources of light is employed for lighting interiors and is located near the ceiling, it is desirable to have a certain portion of the light from the lamp thrown upon the ceiling to illuminate it, and thus soften or eliminate the shadow of the reflector. To accomplish this result, I have employed a number of dispersing devices, such as lenses 9. These lenses or other dispersing devices are placed in apertures formed for the purpose in the reflector. Any suitable means .for holding these devices in place may be employed. In Fig. 2 I have illustrated the lenses 9 as ar- 5 ranged in a circle about the center of the reflector and held in place by fingers 10, which are integral projections from the body of the reflector 4c. These fingers are arranged to hold the lenses 9 somewhat in the manner that jewels are held in their setting. The lenses 9 are proportioned and arranged to furnish the desired amount of illumination upward and to give it the proper amount of dispersion.

Preferably a translucent shade l is carried by the lamp structure below the arc. In the construction shown in the drawings this shade is bell-shaped. This shade serves to cut off some of the direct illumination immediately below the arc and also assists in dispersingthe light. The particular arrangement of conical reflector and bell shade shown in Fig. 2 possesses the additional advantage that it minimizes or prevents changes in the distribution of light when the are shifts as it travels round the carbon ends or the electrodes waste away.

In the construction shown in Figs. 1 and 2 the ridges 8 are concentric with respect to the lamp. In the construction shown in Fig. 3, however, strictly speaking but one ridge or corrugation 12 is formed on the reflector, as is clearly shown in the drawings. This ridge is in the form of a spiral which extends from the center of the reflector outward. The amplitude or height of this ridge or corrugation measured in a direction perpendicular to the general surface of the reflector increases with the distance from the center. The light distribution obtained with this reflector is substantially that obtained with the form shown in Figs. 1 and 2. With some methods of construction it may be desirable, however, to use the form shown in Fig. 3 rather than that shown in Figs. 1 and 2.

It will of course be understood that the lenses 10 may be employed in connection with the form shown in Fig. 3 as well as with that shown in Figs. 1 and 2, and that under some circumstances the lenses 10 may be employed in a construction which does not have the curved ridge or ridges.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. A reflector formed with a spiral ridge or corrugation upon its reflecting-surlace.

2. A reflector formed with a spiral ridge or corrugation upon its reflecting-surface, the amplitude or height of the ridge or corrugation varying progressively along the ridge.

3. A reflector having a circular outline and formed with a ridge or corrugation on its reflecting-surface which extends in spiral turns from the center of the reflector outward, the

amplitude or height of the corrugation increasing along the ridge from the center outward. 4. A reflector having a circular outline and formed with a ridge or corrugation on its reflecting-surface which extends in spiral turns from the center of the reflector outward, the amplitude or height of the corrugation increasing along the ridge from the center outward, and dispersing-lenses located in apertures formed for the purpose in said reflector. In witness whereof I have hereunto set my hand this th day of October, 1903.

WALTER DA. RYAN. Witnesses:

DUGALD MoK. MoKILLor, JOHN A. MoMANUs. 

